MPs heard this week that the position, due to be filled within the next two months, is compromised by the legislation which created it. There could be clashes with the commissioners across the borders.
Critics have already dubbed the post a "toothless tiger" because of a lack of autonomous powers of investigation and freedom from political control.
However, although the English commissioner will effectively be weaker than the other three - because he must seek ministers' approval before launching an investigation - he or she will have some power in their countries.
This might include conducting an investigation in any of those countries without consulting the local commissioner.
Peter Clarke, children's commissioner for Wales, told the Commons education select committee: "It is a recipe for confusion.
"Hopefully, over time, we will get children to understand who is the champion of their rights and that now there are going to be two with different powers and remits. It is going to be a problem."
Mr Clarke said the Government consistently referred to the English post as "our commissioner", showing its lack of independence.
Nigel Williams, the commissioner for children and young people for Northern Ireland, told MPs: "The Government has not made it easy for us in terms of the way the role has been set out."
Kathleen Marshall, the commissioner for children and young people in Scotland, criticised the lack of emphasis on children's rights in the English remit.
The commissioner in England will have responsibility for promoting awareness of the views and interests of children, rather than specifically promoting and safeguarding their rights.
She said: "The Scottish legislation promotes and safeguards rights, which include the interests of the child. There is a moral authority there."
Last month the children's minister, Margaret Hodge, described any fears of clashes between the commissioners as "deeply exaggerated".
However, children's charities also expressed concerns over how the role would evolve.
Peter Newell of the Children's Right Alliance for England and adviser to the European Network of Ombudspeople for Children, told the committee: "I am in a state of bewilderment that what we have been left with is a weak commissioner compared with the rest of Europe."